In this project various aspects of immunological reactions to haptens on autologous carriers are being studied. We have established that T-cells are necessary in the priming of animals to the hapten 4-hydroxy-3-iodo-5-nitrophenyl acetic acid coupled to mouse gamma globulin (NIPMGG). Though haptens are more likely to tolerize B-cells, our experiments indicate that T-cells also become tolerized with this conjugate. Further studies in this project will assess the effect of allogenic cells in regulating tolerance induction to this hapten. We will also determine whether tolerant cells are active in vitro in either activating immune cells or in suppressing the response of these cells to the antigen. The immunogen will be NIPMGG in complete Freunds adjuvant and the tolerogen soluble NIPMGG. In this project we are also investigating possible age related changes in the kinetics of tolerance induction. Immunological functions wane with age. Whether the ability to be tolerized with haptens on autologous carriers also wane with age will be investigated. The role of macrophages from different sources (such as spleen, peritoneal cavity and lungs) in activating immune cells to NIPMGG is also being investigated. BIBLIOGRAPHIC REFERENCES: Age Related Changes in Cell-Mediated Immunity in BALB/c Mice by C. S. Walters and H. N. Claman. J. Immun. 115: 1438, 1975.